1. Technical Field
The present invention relates to a liquid ejecting apparatus including a piezoelectric element having an electrode and a piezoelectric layer that generate a pressure change in a pressure generating chamber communicating with nozzle openings and to a manufacturing method thereof.
2. Related Art
As a representative example of a liquid ejecting head mounted on a liquid ejecting apparatus, there is an ink jet type recording head in which a portion of a pressure generating chamber communicating with nozzle openings from which ink droplets are discharged is configured by a vibration plate, and which discharges an ink as the ink droplets from the nozzle openings by deforming the vibration plate using a piezoelectric element and pressurizing the ink within the pressure generating chamber.
The piezoelectric element used in the liquid ejecting head has a configuration in which a piezoelectric material with an electrical-mechanical conversion function, for example, a piezoelectric layer made of a crystallized dielectric material is interposed between two electrodes. Such a piezoelectric element is mounted on the liquid ejecting head as an actuator device of a flexure vibration mode. Herein, as a representative example of the liquid ejecting head, for example, there is the ink jet type recording head in which a portion of the pressure generating chamber communicating with the nozzle openings from which the ink droplets are discharged is formed of the vibration plate, and which discharges the ink as the ink droplets from the nozzle openings by deforming the vibration plate using the piezoelectric element and pressurizing the ink within the pressure generating chamber.
The piezoelectric material used as a piezoelectric layer configuring such a piezoelectric element requires a high piezoelectric properties and as the representative example of the piezoelectric material, there is lead zirconate titante (PZT). However, a piezoelectric material (non-lead piezoelectric material) which is obtained by removing or suppressing the content of lead has been required from the viewpoint of environmental problems. As the piezoelectric material that does not contain lead, for example, a material having a perovskite crystal structure of barium titanate has been suggested (for example, see JP-A-2004-6722). In addition, as the piezoelectric material that is obtained by suppressing the content of lead, for example, a mixed crystal material of non-lead piezoelectric material and PZT base material is exemplified.
The piezoelectric material made barium titanate series has been primarily considered as the piezoelectric material in bulk, but has not been much considered as a thin film formed on a substrate by a chemical solution method or a sputtering method. Since the piezoelectric layer made of a complex oxide that is obtained by removing or suppressing content of lead does not have a sufficient displacement amount compared with lead zirconate titanate (PZT), it is necessary to have an improved displacement amount and a stable drive.
Such a problem occurs in not only the ink jet type recording head but also in other liquid ejecting heads discharging droplets other than ink. In addition, such a problem also occurs in the piezoelectric element used in addition to the liquid ejecting head.